Economizing air-conditioning cycle



Patented Aug. 10, 1937 UNITED STATES PATENT OFFICE ECONQMIZING AIR-CONDITIONING CYCLE Application August 8, 1936, Serial No. 94,978

4 Claims.

The present new and improved air-conditioning cycle is provided for the purpose of maintaining a' relatively-constant, predetermined, drybulb-thermometer temperature and relative hu- 5 midity in a room or rooms, regardless of size, and, in order to accomplish this favorable result, it is necessary to cool and dehumidify a volume of air so that the heat gain and moisture pickup in this conditioned space will just maintain l0 the desired condition, from which it is evident that the air entering the room or rooms will have f to be colder and less humid than that of the room or rooms themselves.

Likewise, for maintaining a pleasant and comfortable atmosphere, it is advisable to supply a constant volume of fresh air from out-of-doors. There are a considerable number of ways in which this desirable outcome may be accomplished, but the majority of these systems are 2o expensive to operate, and, accordingly, it is one purpose of this invention to provide an air-conditioning cycle whereby an ice or refrigerating machine,` driven by a gas-engine, provides the sensible cooling or` maintains the dry-bulbthermometer temperature, and the relative humidity is kept by dehumidifying with a suitable adsorptive material, reactivated by the wasteheat from the gas-engine.

The utilization of such normally unproductive or unprotable heat for revitalizing the adsorptive agent increases the efficiency of the overall plant to the extent of the latent heat load of the air-conditioning equipment which In some installations is as high as 50% to 60% of the 3`5 total load.

In addition to obtaining free or substantially expenseless dehumidiiication, the load on the ice or refrigerating machine is entirely sensible cooling, thereby eliminating the necessity of operat- 40 ing at a suction gas temperature below the dewpoint temperature of the air.

In normal practice, it is necessary to operate at a suction gas temperature of the refrigerant of Fahrenheit, while with the new and im- 45 proved cycle of this invention, it is possible to operate at a suction gas temperature of 60 Fahrenheit, with a resultant increase in the ca'- pacity output of the refrigerating-compressor as high as 28% and a decrease in the horse-power per ton of refrigeration of 62%.

The complete cycle of the novel and improved air-conditioning plant'is shown diagrammatically in the single ligure of the drawing presented to enable those familiar with the art to understand the various relations between the connections of the air, water, gas and refrigerant, and the relationship of one to the other, or others.

In this apparatus, the refrigerating-compressor I, which may be of the reciprocatory or rotary type, and which can use any one of the many well-known refrigerants, is driven, either directconnected, as at 3, or belt-driven, by means of a gas-engine 2, whereby the refrigerant is compressed by the compressor I and discharged at a relatively-high pressure into the discharge-line 4 at the point 5, such refrigerating medium flowing through such conduit 4 and entering the condenser l at the point 6, this condenser, which may be any one of several types, being preferably of the evaporative-condenser style, wherein the refrigerant flows inside of a series of pipes Il and the heat is removed by` the proper proportion of air and water flowing around the outside of such pipes, the water referred to being used continuously over and over again and circulated by an appropriate pump I8 of suitable design.

'Ihe air which is continuously supplied in fresh condition, is taken from out-of-doors, or from any space in the building not conditioned, at I9. and by means of a fan 20 is blown over the condenser-coils I1 and discharged out-of-doors at 2 I.

Such water asV is evaporated into this air is supplied in the same proportions from a source of supply 22, as for instance the city water-main, and its admission to the condenser is controlled by means of a common, ball-iioat-operated Water-valve 23.

In this condenser l, the refrigerating agent is cooled and converted from a gas at high pressure into a liquid at the same high pressure, which is accumulated in the receiver or reservoir 8 at the lower portion of the condenser and which leaves such receiver at the point 9 and ows through a liquid line I0 to an expansionvalve II of the ordinary type where the pressure is reduced from the discharge pressure to the suction pressure with a resulting drop in temperature. this cold liquid entering the direct-expansion, sensible-heat-control, refrigeratingcoils I2 at the point I3, and in these coils heat from the air is absorbed by the liquid refrigerant which boils into a gas at the same cold temperature (assuming no superheat).

` This cold refrigerating medium leaves the coils I2 as a gas at the point I4 and ows through a suction line I5, entering the compressor I at the point I Ii, this cycle being continuously repeated vwith a resulting continuous production of refrigeration, the purpose oi this part of the plant The dehumidification part of the apparatus may be described as follows:

Fresh air is taken from outside of the room 24 to be conditioned through grilles or louvers 25 and it passes through preheating-coils 26, not then in use for this particular phase of the operation, and then it flows into the adsorber 21 which is lled with an adsorbent material,

suc-h as silica-gel, activated-alumina, or lamisilite, it being a well-known fact that, when air passes through a bed of such material, the air is fully or partially dehumidied, and, in this instance, the exact amount of moisture removed can be controlled by a humidistat 28 in the room which governs a damper 29 controlling the amount of air passing through the adsorber 21.

'I'his dehumidied air then passes over a set of water-cooled cooling-coils 3l where the sensible heat generated in the adsorber 21 and some of the heat originally| in the outdoor air is removed, vthis dehumidif'led and partially-cooled air then mixing at 51 with the recirculatedl air 30 from the conditioned space or room 24 and passing through the direct-expansion cooling- 35 coils I2 where it is reduced to the necessary temperature to maintain a. predetermined temperature in the room 24.

This cooled and dehumidied air then ows to a fan 32 by .which it is blown into the room or rooms 24 through the inlet or admission grille or grilles 33.

'I'he dry-bulb-thermometer temperature in the room 24 is controlled by a thermostat 34 which operates a. lby-pass damper 56 to by-pass some of the air around the coil I2 or such control may be brought about by many other methods now in common practice;

In this cycle, there are two adsorbers, 21 and 35, and while one for example 21, is dehumidifying the air, the other 35, is being reactivated or reenergized.

Fresh air taken from the outside through the grille or louver 36 passes through preheatingcoils 31 where the air temperature is increased to about 180 Fahrenheit, this heat being extracted from the water leaving the cooling-jacket of the gas-engine 2 hereinafter more fully described.

Such preheated air is then heated to about 250 Fahrenheit by the exhaust-gases from the engine 2, this being accomplished by mixing the exhaust-gases directly with the air or by means of a heat-transfer surface.

Such heated air then flows through the adsorber 35 driving the water or moisture from the adsorbent material into the air, and this air is then picked up by the action of an exhaust-fan .38 and discharged outdoors through the'exhaustlouvers 39.

The operation is so arranged that one adsorber is dehumidifying while the other adsorber is being reactivated, and when one adsorber is saturated, the other adsorber is cut in to dehumidify and reactivation of the rst one starts, this shift from one to the other being accomplished by a .cut-over plenum-chamber 40, and when adsorber 21 is dehumidifying, the damper is in position as shown in full line at 4I, and when adsorber is dehumidifying, the damper is in a position shown in dotted line as illustrated at 42.

When adsorber 21 is dehumidifying, three-way valves 43 and 44 are so arranged that the hot water from the engine water-jacket passes through the preheating-coil 31, and, when adsorber 35 is dehumidifying, three-way valves 43 and 44 are adjusted so that the hot water passes through the preheating-coil 26.

The exhaust-gases leave the gas-engine 2 at the point 45 and, when adsorber 21 is dehumidifying,' the three-Way valve or damper 46 directs the hot gases to adsorber 35, and, likewise when adsorber 35 is dehumidifying, the hot gases are directed to adsorber 21 for reactivation.

If, in some plants, the dehumidilcation requirements are severe, an auxiliary heating means can be provided to supplement the deficit of heat of the gases of the engine-exhaust.

The water-cycle is as followsz-The waterpump I8 takes lwater from the pan 41 at the bottom of the condenser 1 and discharges it to three points; pipe 48 delivering the necessary volume of water over the condenser-coils I1 for the purpose of liquefying the refrigerant, the water at the pump suction being maintained at the wet-bulb-thermometer temperature of the air being blown through the condenser by fan 20; pipe 49 delivering the necessary water to the precooling-coil 3|, this water being returned to the condenser through pipe 50; pipe 5I delivering the required volume of water to the coolingjacket of the engine, where the temperature `oi such water is increased to about 190 to 200 Fahrenheit, such hot water iiowing out of the engine-jacket through pipe 52 to the preheatingcoils. either 31 or 26, depending upon which unit is being reactivated, this, of course, preheating the air for reactivation, this water now, at about 120 Fahrenheit, being returned to the evaporative-condenser 1 by means of a pipe 53 and it is cooled to the wet-bulb-thermometer temperature of the air.

The gas-supply to the engine 2 comes from the gas-main 54 and ows through pipe 55 to the carburetor of the engine.,

Whereas the system illustrated and described in detail refers to a gas-engine, it is to be understood that the invention broadly covers the use of steam, gas, vapor or other style of engine, the

waste heat therefrom being employed for the purpose indicated.

By means of employment ot the principles herein outlined, it will be obvious, that this new invention uses a portionof the waste energy of the cooling-system to effect the reactivation of the dehydration means ;l or, stated somewhat difi ferently, the invention involves the employment of the cooling system economically to obtain free dehydration.

'I'he invention, as dened in the appended claims, which should be construed as broadly as permissible by the state of the prior art, is susture in the air and not necessarily in the limited meaning of elimination of lallmoisture.

Whereas hereinbefore the appliances 21 and 35 have been referred to as adsorbers, it is to be understood that, if preferred, they may be absorbers, the functions of the two means being,

comparable.

I claim:

1. In an air-cooling and dehumidifying system, the combination of means to dehumidify the air to be cooled, a refrigerant-compressor, a condenser receiving the refrigerant from said compressor, means to permit expansion of the refrigerant discharged fromsaid condenser, means to cool the dehumidied air by such 'expansion of the refrigerant, a heat-actuated prime-mover operating said compressor, and means employing air heated by waste heat from said prime-mover to reactivate said dehumidifying means.

2. In an air-cooling and dehumidifying system,

the combination of means to dehumidify the air' to be cooled, a refrigerant-compressor, a condenser receiving the refrigerant from lsaid compressor, means to permit expansion of said refrigerant discharged from said condenser, means to cool the dehumidied air by such expansion of the refrigerant, a heat-actuated prime-mover operating said compressor, means to reactivate said dehumidifying-means by air heated by waste,- Ivieat from said prime-mover, and means to preheat said reactivating air by waste heat from said prime-mover.

3. The system presented in claim 2 in which said prime-mover is a Water-cooled internalcombustion engine, said preheating-means is heated by heat extracted from the cooling-water of said engine, and said reactivating-me'tns is heated by heat derived from the exhaust-gases ofsaid engine.'

4. The structure presented in claim 2 in which said dehumidifying means comprises a plurality of adsorbers and means to render said adsorbers active singly, in which said waste-heat reactivates said adsorbers while they are, inactive, and in which said prime-mover is a water-cooled internal-combustion engine, said Preheating means is heated by heat extracted from the cooling Water of said engine, and said reactivating-means is heated by heat derived from the exhaust-gases of said engine.

ROBERT A. WIT'I'MANN. 

